I dont believe its valid on the scale that they want to advance the narrative, how about that. I have NOT seen any credible evidence that climate change IE mans existence has impacted NEGATIVELY the climate we live in. Alaska is still cold, hawaii is still hot. I think both sides can make an argument, but not an infallible one.
I also can concede that man probably has had SOME impact on the environment but to what extent we cannot possibly know conclusively. If youre asking me if man causes polution? sure. does pollution cause climate change? not conclusively. not IMO.